The use of partially and/or fully ²H-labeled samples enables NMR investigations of larger biomolecules as the major cause of ¹³C line broadening and signal losses is eliminated, that is, the major source of the carbon relaxation (the dipolar coupling to the attached protons) is removed.

Since almost every probe is equipped with a deuterium lock channel, the only additional hardware required for deuterium decoupling is a free RF-channel and a switch, which allows alternating the lock channel between locking and decoupling during the experiment. This switch is installed in the 2H-TX board in the console.

The calibration of the deuterium decoupling pulse is done on the ATM sample consisting of 60% benzene-d6 in p-dioxane. First do the ²H-recabling by changing the RF-routing to enable ¹³C observation. In the edsp display select 13C through F1 channel. Deuterium should be routed from the F4 channel through the 300.0 W amplifier, which is now replaced by the 20.0 W TX-amplifier because of the recabling. Save the RF-routing and exit the display. Now read in a pulse sequence called decp902hf4.

Acquisition parameters for deuterium pulse calibration

PULPROG decp902hf4.
NUC1 13C
O1P 128 ppm
NUC4 2H
O4P 7.28 ppm
NS 1 
DS 0
CNST5 25

Since deuterium is a spin 1 nucleus the resulting spectrum contains a triplet instead of the doublet of a spin 1/2 nucleus. Fig. 10 shows the three cases from the calibration. At the 90 o -pulse the outer lines are at minimum and the middle line at maximum.

The required pulses to be applied from the ²H or f4 channel are:

1H 90 decoupling pulse (pcpd4=200-300us) at low power level (pl17) using cpdprg1=watlz16.

Also see Tutorials: Pulse Calibrations